An internal combustion engine may include port fuel injector and direct fuel injectors. The port fuel injectors may be operated at different times than the direct fuel injectors, or alternatively, the port fuel injectors may be operated at a same time as the direct fuel injectors. For example, at lower engine speeds and loads, only port fuel injectors may be operated. At middle engine speeds and loads both port fuel injectors and direct fuel injectors may be operated. However, if a direct fuel injector exhibits reduced performance or degradation, it may be difficult for a cylinder with a degraded direct fuel injector to operate in a same way as a cylinder that has a port fuel injector and a direct fuel injector that are not degraded. For example, the cylinder with the degraded direct fuel injector may knock at lower engine loads than the cylinder having the direct fuel injector that is not degraded. Therefore, it may be desirable to provide a method for operating an engine with a degraded fuel injector that mitigates undesirable engine operation.
The inventors herein have recognized the above-mentioned disadvantages and have developed an engine fueling method, comprising: receiving inputs to a controller; and deactivating a port fuel injector of a first cylinder in response to reduced performance of a direct fuel injector of the first cylinder based on the inputs to the controller.
By deactivating a port fuel injector of a cylinder with a degraded direct fuel injector, it may be possible to provide the technical result of reducing the possibility of further degradation. For example, the port fuel injector of a cylinder may be deactivated so that a direct fuel injector of the same cylinder is not exposed to higher temperatures, thereby reducing the possibility of further direct fuel injector degradation. Additionally, output of the engine's remaining cylinders may be increased so that a desired engine torque may be provided by the engine cylinders that remain active.
The present description may provide several advantages. For example, the approach may reduce the possibility of increased engine degradation. In addition, the approach provides for providing a desired amount of engine torque in the presence of direct fuel injector degradation, at least during some conditions. Further, the approach provides for a repeatable way of mitigating direct fuel injector degradation.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.